Generally, X-rays, MRI, ultrasonic waves and the like are used in imaging an internal structure of a human body or object. Specifically, in order to image electrical characteristics of a human body or object, many efforts have been made to image a current density within a measurement target using an MRI technique.
As a technique for imaging electrical characteristics of a human body or object, there is EIT (electrical impedance tomography) having been actively researched and studied since 1970's.
The EIT technology provides a resistivity or conductivity image indicating electrical characteristics of a measurement target. By mainly targeting a human body as a measurement object, the EIT technology images conductivity within the human body in a manner of attaching a plurality of electrodes to a surface of the human body. In particular, after a current has been applied via a plurality of the electrodes attached to the surface of the human body, the conductivity within the human body is imaged by measuring voltages via the electrodes. Thus, the internal part of the human body can be imaged according to the conductivity. This is because living organs including blood, bones, lungs, heart and the like differ from one another in electrical characteristics.
However, in case of measuring a voltage of a human body using the related art EIT technique and instrument, the measured voltage contains various kinds of noises. Since these noises make it difficult to precisely detect the electrical characteristics of various organs of the human body, it is unable to precisely image the internal part of the human body.
Moreover, the conventional EIT instrument includes too many devices, whereby its configuration is considerably complicated. Hence, the conventional EIT instrument has a considerably large size and a high product cost.